Radio loud speaker



Nov. 8, 1927. 3 v

I W. WESTPHAL RADIO LOUD SPEAKER- Filed March 1926 24 I Z J I l 20 i i I i I I" I 50 5 M. 4 68 67 42 9 40 magnet illustrating the Patented Nov. 8,1927.

PATENT OFFICE.

WALTER WESTPHAL, 01? LOS ANGELES, CALIFORNIA.

- RADIO LOUD SPEAKER.

Application filed larch 30, 1926. Serial No. 85,502.

My invention is aradio loud speaker and.

in the mechanism for vibrating a. diaphragm by means of an electric current, the invention being principally in the manner of mounting an electric-magneticdevice in relation to the diaphragm to vibrate same in accordance with the electric current from a radio receiving instrument. f An object of my invention is to manufac- '10 'ture'the holding device for the diaphragm, to make a magnet, pole pieces, a spool, etc'., on which the'windings of an electro-magnet are wound so that practically all the elements may be madey die-pressing, in to a minimum extent the amount of inachlne cutting or filing etc., that may be necessary. c

In the structure ofmy loud speaker, an objectof my invention is to utilize a flat horseshoe magnet to secure die-pressed ole pieces to opposite ends of the'magnet, t ese pole ieces being-utilized to properly center an e ectro-ma net wound on a spool, the spool being ormed by die-pressing and soldering and to mount an armature direct-1y in the s 001 without the necessityof a sleeve or the like around the armature. I utilize a bolt in the ordinarymannerto transmit the vibrations from the armature to the diaphragm.

My invention will be more readily understood from the following description and drawings, in which; a

Figure 1 is a. plan view of my loud speaker taken in the direction of the arrow 1 of Fig. 2;

Fig. 2 is a vertical section on. the line a-2of F g. 1.

' Fig. 3 is an end view of the horseshoe ole pieces broken away, and showing the dlaphragm holder in elevation, the view being taken substantially in the direction-of the arrow 30f 1';

i Fig. 4 is an elevation taken in the direction of the arrow- 4 of-Fig. 1;

Fig. 5 is a side elevation of the. elements ofthe spool before being connected together; I

Fig. 6 is an end view ofr-the elements of the spool viewed in the directidn'of either of the arrows 6 of Fig. 5;

Fig. 7 is a plan of the upper section of reducthe spool frame, taken in the direction of the arrow 7 of Fig. 5;

Fig. 8 is a bottom view of the upper section of the spool frame taken in the direction of the arrow 8 of Fi 5;

Fig. 9 is a longitudinal section of the spool frame assembled.

Fig. 10 is an alternative construction of a spool showing an alternative mounting for the armature. y I

Attention is first directed to-the constructionof the diaphragm holder on which the electro-maguet to vibrate the armature is supported. A supporting plate 1 is preferably made circular and is formed in a diepress forming a substantially flat plate 2 with a tubular center part 3 through which the sound is conducted to a. horn or the like. The edges of the plate have an upturned rim 4. An annular indentation or groove 5 is formed by die-pressing from the outside, this an annular ridge 6 upwardly. A

pressin rests on this ridge and the diagasket phragm 8 rests on the gasket. An upper gasket 9 is placed on top of the diaphragm and is wedged down tightly thereon by a clamping plate 10. This plate is also of circular construction and has a slightly downwardly pressed annular edge '11 through which the securing screws 12 are fastened.

There is a slight space between the supporting plate and the clamping plate as indicatedby the numeral 13 so that these plates can be tightly secured togetheig-by the screws 12. This clamping plate has a series of upwardly pressed nubs 14 adapted to position the magnet and pole pieces of the electro-magnet: The clamping plate has a central opening 15 to' allow connection from the electro'magnet to the diaphragm as hereunder set forth.

The electro-magnet is constructed with a horseshoe magnet 20, this latter being made flat with o posite poles in the same plane. A lower p0 e piece 21 is formed with a base '22, opposite sides 23. andan end 24. These sides and the one end are bent upwardly in a die-pressing operation. The lower pole piece is secured to one pole of the magnet means .of a screw 25which'passes into t e end 24. v

The upper polepiece 26. has a top 27, op-

posite sides 28 and an end 29. The two sides andthe single end are bent into shape m a die-pressing o eration. The upper pole piece is secure to the opposite pole of the magnet, to the lower pole piece, by means of a screw 30 extending through such-pole and into the end 29. It will thus be seen'that the pole pieces are rigidly secured to the oposite poles of the permanent magnet and orm upper and lower channels 31 and 32 in which the spool having electric wiring and the armature are'inserted. The spool and the manner of makin same is substantially as follows, having re erence particularlyto Figs. to i);

The spool has upper and lower 580510118 33 and 34, these being of similar constructlon and formed by die pressing. The center portion 35 is fiat, having slightly otfset pressed, ends 36 with upwardly bent opposite sides 37. The sides at each end have outwardly extending flanges 38. The cor-' ners 39 ma be cut off at an angle if desired or rounded As above mentioned, the two sections of the spool are formed similar so that when the spool sections are placed together the #flanges 38 are slighly flared in an opposite direction as indicated by, the numeral 40,

thus allowing filling with solder. The meeting edgesof the spool sections indlcatedby the numeral 41 extending-lengthwlse of the flanges 38, and the cross edges 42 as clearly shown in Figs. 5 and 9, contact and are secured together b solder. The flanges as above mentioned orm a surface of conslderable extent'to which ap sufiicient body of solder may be secured to form a substantlal s 001. t

It will thus be seen that when the spool elements are assembled,that a rectan lar opening 43 extends from side to side 0 the spool as shown in Fig. 9. Afterthe spool is constructed a cut 44. is made transversely across the upperx-section of such spool, cutting the side walls 33 and the base or flat surface35, as in'dicated by the dotted lines.

in Figs. 5*and 7 and by the full lines in Fi 9. r The armature andthe manner of securingsame in place is substantially as' follows, having reference-particularly ,to Figs. 5, 7, 8 and9: v;

- The armature 45 is substantially rectangular having however, projections 46 at oppo-,.-

site ends. A slight groove 47 is cut in the lower surface ofthe armature and a plural ity of drilled holes 48 at each end of the groove. The center portion or center'plate 35 of the spool hasa pair of drilled holes 49 to register with those of the armature and has a slightly counter-sunk portion indicated by the numeral 50 at the upper end of said drilled holes, A suspending wire 51 fits in the groove of the "armature and ex- The lower connector is ins the usual insulation 52 is placed between the copper of the frame and the wire.

The assembly of the pole pieces and spool is substantially as follows, having reference particularly to Figs'l to 4:

As above mentioned the flanges of the spool frame are secured together by wire and form a stiff frame, these flan es being slightly flared apart. The ends 0 the pole pieces fit against these flanges as indicated y the numerals 53 and 54; thus tightly securing the spool in the pole pieces. The ends 55 of the spool frame fit snugl in the ends 24 and 29 of the pole pieces. The side of the spool frame is slightly spaced from the base 22 and the top 27 of the pole pieces as it dicated by the numeral 56. A bolt 57 is vsecured to the center projection 46 of the armature, extends through the opening 50 in the clamping plate and is attached to the di aphragm as indicated by the numeral 58.

Usually the bolt is secured by solder to the pro]ect1on 46 and has very fine threads at its other end, and is adjustably secured to' the diaphragm by means of thin threaded washers on opposite sides of the dia hragm and a lock nut on the lower side. he pole pieces are securely fastened to the clamping plate by means of rivets 59 which extend.

through the base 22 of the lower pole piece, these rivets having .cou'nter-sunk heads at both ends. The electro-magnet and the pole pieces rest on the nubs 14 upwardly pressed from the clamping plate.

The electrical connectors are secured to a bolt 60 positioned centrally between the arms of the magnet; this bolt extendin upwardly. through the clamping late. ach of'the connectors 61 is formed y a strip of metal having-a punched-out tongue62 with a screw63 through the p, ecuring the terminus 64 of the electric lead wire in fposition. ulated rom the clamping plate and the connectors insulate from each other and from the nut on the bolt -60 by insulation washers64. The free ends 65 of the connectors extend over the permanent magnet, having a stripf66 of insulation therebetween. Thus the connectors function sition in relation to the clamping plate. Electric leads 67 extend from'the connectors to the winding 68 of the spool.

to hold the permanent magnet firmly in pospeaker 'm'ay' From the above descri tion it will be seen that praoticall all the e ementsof my loud made by die-pressing the different parts, requiring ve little-machine work, fili or grinding. e operation is believed to be obvious, the fluctuations of the In Fig. 10 the spool is illustrated as pro-' vided with a hook adapted to engage a complementary hook 71 on-the armature. These hooks are so arranged that the armature is balanced when the hooks are in engagement andallow free tilting of the armature as it vibrates. The'bolt '57 leading to the diaphragm prevents the armature from becoming unhooked from the hook in the spool, this action being aided by a bentpin 72 having one end fitting in a hole 7 3 in the I upper ole iece; the free end of the pin having a ree t through an aperture. 74 in the armature.

Having described my invention, what I claim is: a

1. In a radio loud speaker, a U-shaped flat permanent magnet, a lower pole piece connected to one ofthe poles, an upper pole piece connected to the other pole, the said pole pieces being channel-shaped, a spool having electric wiring mounted in the pole pieces wit-h a transverse opening therethrough, an armature suspended in the trans verse opening of the spool, the pole pieces having a closed end, the closed end being secured to the poles of the magnet, the end of one pole piece being longer than the other, thereby positioning such pole pieces directly above the other.

2. In a radio loud speaker, a supporting plate of circular shape having an upwardly ressed annular groove on the outside formmg an inwardly pressed ridge on the other side, a diaphragm resting on said ridge, a

clamping plate bearing on the diaphragm,

and means to secure the clamping plate/and supporting plate tightly together, there being gaskets between the diaphragm and the supporting and clamping plates.

3. In a radio loud speaker as claimed in claim 2, having in addition an upwardly turned rim on the supporting plate, a downwardly pressed annular edge on the clamping plate, there being a series of screws ing throu h the annular edge and the support ing 1) ate forming a; meansto clamp same we -i 4. In a-r'adio' loud speaker, a flat U-shaped magnet, a pair of channel-shaped pole ieces, the lowermost polepiece having an en closing one" end'of the channel, the end being secured to the "inside of one of 'themagnet poles, the upper pole iece having an end longer than the end of t e lower pole piece extending downwardly, closing one'end of the upper pole iecc,'and being connected to the inside of t e opposite pole of'the magnet.

5. In a radio loud speaker,'a spool having a pair of opposite flat sections spaced apart,

side walls extending beyond said .sectlons, the side walls being secured together by solder, the flat sections being spacedapart and forming a transverse opening.

6. In a radio loud speaker, a spool formed of complementar parts, each of said parts having a central at section, inwardly pressed ends at the end of said section, adapted when assembled to form a transverse passage through; the ,spool, there being. side I walls extending in opposite directions from the flat sections, outwardly extending flanges .on the sides, the flanges being secured together,

7. In a radioiloud speaker, a spool formed of complementar parts, each ofsaid parts having a central at section, inwardly pressed ends at the ends of said sections, adapted when assembled to. form a transverse passage through the spool, side walls extending in opposite directions from the fiat ,sec-' tions, wall extensions beyond the ends of said flat sections, and means to secure the wall extensions together. ,i

8. In a radio loud speaker, a flat U-shaped magnet having parallel upper and lower faces, a pole piece having an end secured to one ofthe ends of the magnet on the inside, achannel member secured to said end with thebase of'the channel inJalinement with the lower surface of the magnet, an

upper pole piece having an end secured to a the other end of the magnet and extending above the top of the magnet, a channelshaped structure connected to the said latter end and extending over the lower channel pole piece, the sides of the channels being contiguous one to the other.

9. A radio loud speaker comprising in combination a supporting plate and a clamp- Elate having a central opening and a diap ragm clamped therebetween, a channelshaped' lower pole piece secured to the clamping plate, a flat U-sliaped magnet havmg one pole secured to the said pole piece,

the magnet being adapted to rest on the clamping plate, an upper pole piece longer than the lower pole piece secured to the opposite pole of the magnet, forming an intoo tt ha nel ov th ow r P e p ece, a he lw m g lm {1, 9 im sns Q said eonspool ing a an s s' pe g th enect m =e' i en m' 9V9}? be ,m ifiet; and thr'ou' h and. havingpp electric Windipg sup adflpted to hpljd'saigi ygg gipjsp 1Q 

